John teegoning



J. TREGONING.

CARBON HOLDER FOR ELECTRIC LAMPS.

(No'Molel.)

,324'. Patentd Feb. 7,1882.

,the lower part of the same.

- UNITED STATESy PATENTl OFFICE.

JOHN TREGON ING, OF NEW YORK, N. Y., ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF SAME PLACE.

CARBON-HOLDER FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 253,324, dated February 7, 1882.

Application tiled January 19, 1881. (No model.) l

To all whom it may concern:

Be it known that I, JOHN TREGONING, of the city, county, and State of New York, have invented a new and useful Improvement in Carbon-Holders for Electric Lamps, of which the following is a specification, reference being had to the accompanying drawings, forining a part thereof.

It is essential inV an electric lamp of the arc type that perfect electrical contact be secured between the carbons and their sockets in order to prevent thedevelopment of heat at their point of contact, and also to lessen the resistance at that point to the passage of the current. This result has ordinarily been at! tained by the use of screw-clamps by electroplating the ends of the carbon pencils, or by other similar means.

The object of my present invention is to construct a socket for the lower carbon pencil which will be easy of manipulation and will insure a perfect electrical contact; and for this purpose I have devised a modieri form of chuck with ex pandingjaws and tapering socket for holding and clamping the end of the carbon, and securing between the same and the frame of the lamp a good electrical connection.

In the drawings accompanying this application, Figure l represents in elevation the holder in position on the lower cross-bar of the lamp with a portion of the carbon pencil clamped thereby. Fig. 2 is a vertical section of the clamp, showing the expandingjaws entire. Fig. 3 is a plan view of the upper portion of the clamp.

The central portion of the ordinary crossbar of an electric lamp is made slightly wider and thicker than the remaining part, an`d through a slot of circular shape in this enlargement passes the screw-rod g, which clamps the disks a and b of the holder to the upper and lower faces of the cross-bar or yoke. The upper disk, a, is provided with a hub of a shape and size to form a socket with tapering-sides adapted to contain the cup orjaws c, composed of a tleXible or resilient metal, and having longitudinal slots cut therein. Through an opening in the battery of this cup passes the screw g, the head of which lits snugly in a seat in The screw-rod g may be inserted between the disk b and nut c,

passes down through the slot in the yoke and through the center of the lower disk, b. The holder is clamped to the yoke and the expandingjaws drawn down into their socket by means of the nut c on the screw-rod g. A washer, d,

as shown in Figs. 1 and 2.

To use this clamp or holder it is only necessary to loosen thejaws c by unscrewing the nut c. The end of a carbon,f, is then inserted in Y the socket formed b v thejaws e, and the whole is drawn down by the screw into the tapering sides of the interior of the hub a. The result of this is to firmly clamp the carbon pencil and 6 5 hold it in any desired position, and to insure a close Contact between the same and the metal jaws e.

The screw-rod g, by being made independent of the clamping-cup e, can be utilized as 7o a piston for forcing out the stubs of the carbon pencils when they have burned down and it is desired to remove them.

The cross-bar is provided with a circular slot or opening, as above described, of such a size that the carbon-holder may be adjusted laterally with reference to the position of the upper carbon, so that it may be held directly under or slightly to one side of the upper carbon. This arrangement presents great advantages over the usual ball-and-socket joints, from the fact that the carbons by this holder are always maintained parallel to each other, while by the ball-and-socket they are apt to be placed at an angle.

What I claim as my invention is- 1. The combination, with the lower carbon pencil of an electric lamp, of the eXible or expanding jaws e, resting in a tapering socket, a, and adapted to clamp the carbon and to be drawn down into the socket by means of a screw-rod and nut, substantially as described.

2. In combination with the socket and griping-jaws of a carbon-holder, a screw-rod for drawing the jaws down into the socket, and adapted to be pushed up between the jaws for displacing the ends of the carbons retained thereby. Y

JOHN TREGONING. Witnesses:

J osEPH OLMsTED, W. H. CALHOUN, Jr. 

